This invention relates to a scraper assembly for a scraper chain conveyor, and in particular to a scraper assembly for a centre-chain scraper chain scraper chain conveyor.
The channel sections which make up the body of a scraper chain conveyor are connected together end-to-end in a manner that permits adjacent sections to move slightly angularly with respect to one another. This slight degree of angular movement is essential to enable the conveyor to adapt itself to irregularities in the floor of mine workings. Unfortunately, this increases the very heavy stresses to which the chain and scraper assemblies are subjected.
A scraper assembly is known which has a scraper and a locking member which are joined together by means of bolts, and which clamp a link of the chain therebetween. For example, the locking member may have bifurcated ends and may be secured to the scraper by means of horizontal bolts which extend through aligned holes in the bifurcated ends of the locking member and vertical web portions of the scraper. (See DT-PS No. 1,217,863).
A similar construction is known for a double-centre-chain scraper chain conveyor, in which the locking member is likewise secured to the scraper by means of horizontal bolts. (DT-OS No. 2,031,876).
It is also known to connect the locking member of a scraper assembly to its scraper by means of vertical bolts. The bolts may, in this case, be formed integrally with the locking member which is of U-shape. Unfortunately, such an arrangement suffers from the disadvantage that the inevitable damage to the bolts and their threads, which results from working in the rough conditions occuring during mining operations, means that entire locking members become unusuable and have to be replaced. Moreover, vertical bolts are subjected to undesirable shear loads. (See DT-PS No. 1,199,690 and DT-AS No. 2,353,906).
However, if horizontal bolts are used for securing the locking members to their scrapers, the fitting and removal of scraper assemblies can cause considerable difficulties, particularly in the restricted conditions prevailing in underground mining workings. This is particularly the case when the scraper assemblies are spaced relatively closely along the drive chain of the conveyor. It is then often difficult, or even impossible, to apply a pneumatic power tool for tightening the nuts on the bolts when fitting the scraper assemblies, of for loosening these nuts when dismantling the scraper assemblies. The difficulties are enhanced when the drive chain follows a curved path. Moreover, the frequent (and unavoidable) jamming of the nuts, which occurs because of damage or corrosion to the threads of the bolts, often causes considerable difficulties.
When vertical bolts are used for securing the locking members to the scrapers, the tools used to tighten and loosen the nuts must be applied thereto from above, and this can cause considerable difficulties, particularly when only a limited working space is available above the conveyor.
The aim of the invention is to provide a scraper assembly which can more easily and more comfortably be fitted and removed, even when there is only a small working space available above the associated conveyor, or when the spacing between adjacent scraper assemblies is relatively small.